As eight lawmakers arrived at a conference room early Wednesday for another round of negotiations on public school funding, I welcomed them with a nod from my post in the hallway outside the entrance.

I came to take attendance, my way of reminding them someone is watching. I’ve positioned myself outside the same doors ahead of several of these confabs that began March 6.

Participants say they are making progress yet are tight-lipped on specific gains. They appear to be in absolutely no danger of reaching an agreement before the regular legislative session is scheduled to end April 23.

This means the state’s 147 lawmakers are bound for an extra-but-definitely-not-special session — just as many of them predicted at the outset of this 2017 session.

Why is this happening?

Well, consider the task this way: This group is assembling a jigsaw puzzle with around 1,200,295 pieces, each one representing a different student, educator and school district. No two are cut exactly alike.

In fact, different collections of lawmakers have been trying to put this puzzle together since the state Supreme Court issued its decision in the McCleary case in 2012. That ruling requires the state to amply fund a program of basic education in Washington’s public school system by Sept. 1, 2018.

What’s the hang-up?

They don’t agree on how to define basic education. No one seems totally satisfied with how it is now defined in the law. Plenty of Democratic and Republican lawmakers in the House and Senate wish to see early education, college prep and vocational training enjoy equivalent treatment as reading, writing, arithmetic and science. They don’t now.

And there’s no agreement on what “amply fund” means. Negotiators figure it’ll cost around $1.8 billion additional dollars in the next two-year budget and multiply into $4 billion or $5 billion in the budget after that. As to where those dollars come from — a new property tax, a new capital gains tax, a business tax hike, etc. — is a subject of other negotiations.

Deciding what to fund and how much to spend are literally the edges of the puzzle. Then this team of four Democrats and four Republicans must begin the assembling that results so every student receives the same program of basic education.

Negotiators also must make sure the state is paying every classroom teacher, school principal and custodian a competitive wage. This actually consumes most of the new spending because the difference between what the state provides districts for those wages and what districts actually pay those workers is significant. It can range from a few thousand dollars for a new teacher to maybe $30,000-a-year for a veteran instructor, double that for top-flight administrators and superintendents.

That brings up the next hurdle: how the dollars will be distributed.

Majority Democrats in the House want to keep using the existing prototypical school model. The Republican-led Senate wants to use a new one that is based on a spending level per pupil. Democrats argue their method is fairer. Republicans counter that theirs is clearer.

Then there are the local property tax levies. School districts will still need money from local levies to pay for athletics, band and other extras that are not part of basic education and thus not covered by the state. What amount they will be allowed to raise is a question this group is debating.

Finally, there’s no lack of politics influencing this effort.

For House Democrats, one challenge is internal. Several caucus members seem to consider it a higher priority to increase funding for human services and health care programs than for education. These guys want a whole lot more revenue from new taxes than can be achieved this year.

Senate Republicans, meanwhile, are working through a small family problem. It seems some of their GOP brethren in the House are expressing ideas not in sync with elements of the Republican approach.

On Wednesday morning, the eight House and Senate members tried to fit a few more pieces together.

And they all arrived on time.

Political reporter Jerry Cornfield’s blog, The Petri Dish, is at heraldnet.com. Contact him at 360-352-8623; jcornfield@heraldnet.com. Twitter: @dospueblos.